Dynamics of Watershed Ecosystem Values and Sustainability: An Integrated Assessment Approach

 In this work, we undertook an integrated assessment of water and forest ecosystem to develop the value-based sustainability indicators (VBSI) of watershed resource.

This is a new approach proposed to be used to gauge the sustainability of ecosystems goods and services by taking into account the economic values to the local community in place. A conservation idea as implied in the concept of payment for environmental services (PES) through the willingness to pay (WTP) is used to define the sustainability indicators. We employed the DPSIR - Driving forces - Pressure – State – Impact - Response and the Total Economic Value (TEV) frameworks in the process of establishing the VBSI. A multi stage regression analysis was employed to establish environmental, economic and demographic attributes influencing the willingness to pay. The study estimated the marginal effect of each variable on the ecosystem value and these were aggregated to establish the VBSI. We defined and classified watershed resource sustainability indicators based on predictors of ecosystem values represented by the WTP premium in the study area. We argue that extending the horizon to include the economic values when instituting the sustainable watershed resource management is paramount. We estimated the VBSI (=0.25), which was below the average VBSI (=0.5) threshold for the sustainable state. This result indicated that, the watershed ecosystem in the study area not sustainable. Deliberate efforts were needed to address the water resource management in the area.